U.S. patent number 11,192,282 [Application Number 16/116,402] was granted by the patent office on 2021-12-07 for template, template manufacturing method, and semiconductor device manufacturing method.
This patent grant is currently assigned to TOSHIBA MEMORY CORPORATION. The grantee listed for this patent is TOSHIBA MEMORY CORPORATION. Invention is credited to Hirokazu Kato, Kei Kobayashi, Anupam Mitra, Seiji Morita.
United States Patent |
11,192,282 |
Kobayashi , et al. |
December 7, 2021 |
Template, template manufacturing method, and semiconductor device
manufacturing method
Abstract
According to one embodiment, a template for imprint patterning
processes comprises a template substrate having a first surface and
a pedestal on the first surface of the template substrate, the
pedestal having a second surface spaced from the first surface in a
first direction perpendicular to the first surface. A pattern is
disposed on the second surface. The pedestal has a sidewall between
the first surface and the second surface that is at an angle of
less than 90.degree. to the second surface.
Inventors: |
Kobayashi; Kei (Yokohama
Kanagawa, JP), Mitra; Anupam (Yokohama Kanagawa,
JP), Morita; Seiji (Tokyo, JP), Kato;
Hirokazu (Kariya Aichi, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
TOSHIBA MEMORY CORPORATION |
Tokyo |
N/A |
JP |
|
|
Assignee: |
TOSHIBA MEMORY CORPORATION
(Tokyo, JP)
|
Family
ID: |
67683831 |
Appl.
No.: |
16/116,402 |
Filed: |
August 29, 2018 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20190263024 A1 |
Aug 29, 2019 |
|
Foreign Application Priority Data
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Feb 27, 2018 [JP] |
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JP2018-033833 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C
37/0053 (20130101); H01L 21/027 (20130101); B29C
43/38 (20130101); B29C 33/424 (20130101); B29C
43/021 (20130101); B29C 35/0888 (20130101); G03F
7/0002 (20130101); B29C 2035/0827 (20130101); B29C
2043/025 (20130101) |
Current International
Class: |
B29C
33/42 (20060101); H01L 21/027 (20060101); B29C
35/08 (20060101); B29C 43/38 (20060101); B29C
37/00 (20060101); G03F 7/00 (20060101); B29C
43/02 (20060101) |
References Cited
[Referenced By]
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2016225370 |
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Dec 2016 |
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JP |
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Primary Examiner: Hauth; Galen H
Attorney, Agent or Firm: Kim & Stewart LLP
Claims
What is claimed is:
1. A template for imprint patterning processes, comprising: a
template substrate having a first surface; and a pedestal on the
first surface of the template substrate, the pedestal having a
second surface spaced from the first surface in a first direction
perpendicular to the first surface, and a pattern disposed on the
second surface, wherein the pedestal has a sidewall between the
first surface and the second surface that is at an angle of less
than 90.degree. to the second surface, and the sidewall comprises a
first portion that meets the second surface at the angle and a
second portion that extends from the first portion towards the
first surface at a second angle different from the angle.
2. The template according to claim 1, wherein the angle is greater
than or equal to 30 degrees and less than or equal to 45
degrees.
3. The template according to claim 1, wherein the pattern is
disposed in a pattern arrangement region in a central portion of
the second surface surrounded on the second surface by a mark
arrangement region outside the pattern arrangement region between
the central portion and an outer edge of the second surface, and
the pattern arrangement region does not extend laterally along the
second surface beyond an outermost position of a projected outline
of a direct contact region between the pedestal and the first
surface.
4. The template according to claim 1, wherein the pedestal is a
resin material.
5. The template according to claim 1, wherein the pedestal and the
template substrate are formed of the same material.
6. The template according to claim 5, wherein the pattern is formed
in a resin material disposed on the pedestal.
7. The template according to claim 6, further comprising: an
adhesion layer between the resin material and the pedestal.
8. The template according to claim 7, wherein the adhesion layer
comprises at least one of 3-(trimethoxysilyl)propyl acrylate,
3-[diethoxy(methyl)silyl]propyl methacrylate,
3-(trimethoxysilyl)propyl methacrylate,
3-[tris(trimethylsilyloxy)silyl]propyl methacrylate,
3-[Dimethoxy(methyl)silyl]propyl methacrylate,
3-(methoxydimethylsilyl)propyl acrylate, 3-(triethoxysilyl)propyl
methacrylate, 3-(triallylsilyl)propyl acrylate,
3-(triallylsilyl)propyl methacrylate,
diethoxy(3-glycidyloxypropyl)methylsilane,
3-glycidyloxypropyltrimethoxysilane,
3-glycidyloxypropyl(dimethoxy)methylsilane, and
[8-(glycidyloxy)-n-octyl]trimethoxysilane,
triethoxy(3-glycidyloxypropyl)silane.
9. The template according to claim 1, wherein the second angle is
substantially 90.degree. and the second portion meets the first
surface at the second angle.
10. The template according to claim 1, wherein the pedestal is a
first resin material and the pattern is formed in a second resin
material disposed on the first resin material.
11. The template according to claim 1, wherein the pedestal is a
first resin material, and the pattern is a second resin material,
different from the first resin material, disposed on the first
resin material.
12. The template according to claim 1, wherein the pedestal is a
resin material.
13. A method of manufacturing a semiconductor device, comprising:
preparing a template comprising: a template substrate having a
first surface; and a pedestal on the first surface of the template
substrate, the pedestal having a second surface spaced from the
first surface in a first direction perpendicular to the first
surface, and a pattern disposed on the second surface, wherein the
pedestal has a sidewall between the first surface and the second
surface that is at an angle of less than 90.degree. to the second
surface, and the sidewall comprises a first portion that meets the
second surface at the angle and a second portion that extends from
the first portion towards the first surface at a second angle
different from the angle; depositing a resist material on a
semiconductor substrate; placing the template pattern and the
resist material in contact; curing the resist material while in
contact with the template; and separating the template from the
resist material after curing.
14. The method of claim 13, wherein the angle is greater than or
equal to 30 degrees and less than or equal to 45 degrees.
15. The method of claim 13, wherein the pattern is disposed in a
pattern arrangement region in a central portion of the second
surface surrounded on the second surface by a mark arrangement
region outside the pattern arrangement region between the central
portion and an outer edge of the second surface, and the pattern
arrangement region does not extend laterally along the second
surface beyond an outermost position of a projected outline of a
direct contact region between the pedestal and the first
surface.
16. The method of claim 13, wherein the pedestal is a resin
material.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority
from Japanese Patent Application No. 2018-033833, filed Feb. 27,
2018, the entire contents of which are incorporated herein by
reference.
FIELD
Embodiments described herein relate generally to a template, a
template manufacturing method, and a semiconductor device
manufacturing method.
BACKGROUND
In the related art, when a template is pressed against a resist
material on a workpiece during imprint lithography processing, the
resist material seeps out from a periphery of a pedestal portion of
the template on which the imprint pattern is disposed.
DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are views schematically illustrating a template
according to a first embodiment.
FIGS. 2A and 2B are cross-sectional views illustrating additional
aspects of the template according to a first embodiment.
FIGS. 3A to 3E illustrate aspects of a sequence of a manufacturing
method of a template according to a first embodiment.
FIG. 4 is a cross-sectional view schematically illustrating one
example of a template according to a second embodiment.
FIG. 5 is a cross-sectional view schematically illustrating another
example of a template according to a second embodiment.
FIGS. 6A to 6D illustrate aspects of a sequence of a manufacturing
method of a template according to a third embodiment.
FIG. 7 is a cross-sectional view schematically illustrating an
example of a template according to a fourth embodiment.
FIGS. 8A to 8D illustrate aspects of a sequence of a manufacturing
method of a template according to a fourth embodiment.
FIGS. 9A to 9D illustrate aspects of a sequence of a semiconductor
device manufacturing method including a template according to a
fourth embodiment.
FIGS. 10A and 10B are cross-sectional views schematically
illustrating a reproduction sequence of a template according to a
fourth embodiment.
FIG. 11 is a cross-sectional view schematically illustrating a
template according to a fifth embodiment.
FIG. 12 is a diagram schematically illustrating aspects related to
an adhesion layer and a template according to a fifth
embodiment.
FIGS. 13A to 13E illustrate aspects of a sequence of a
manufacturing method of a template according to a fifth
embodiment.
FIG. 14 is a cross-sectional view schematically illustrating a
template manufactured by a method described in conjunction with a
fourth embodiment.
FIGS. 15A and 15B are cross-sectional views schematically
illustrating aspects of a sequence of a manufacturing method of a
template according to a sixth embodiment.
DETAILED DESCRIPTION
Embodiments provide an imprint template, an imprint template
manufacturing method, and a semiconductor device manufacturing
method using an imprint template which can prevent a resist from
seeping out from a periphery of a pedestal portion of the template
during the imprint processing.
In general, according to one embodiment, a template for imprint
patterning processes comprises a template substrate having a first
surface and a pedestal on the first surface of the template
substrate. The pedestal has a second surface spaced from the first
surface of the template substrate in a first direction
perpendicular (normal) to the first surface. A pattern is disposed
on the second surface. The pedestal has a sidewall between the
first surface and the second surface that is at an angle of less
than 90.degree. to the second surface.
A template, a template manufacturing method, and a semiconductor
device manufacturing method according to example embodiments will
be hereinafter described in detail with reference to the
accompanying drawings. It is noted that the present disclosure is
not limited by these example embodiments.
First Embodiment
FIGS. 1A and 1B are views schematically illustrating an example
configuration of a template according to a first embodiment. FIG.
1A is a top view, and FIG. 1B is a cross-sectional view taken along
a line A-A of FIG. 1A. A template 1 includes a rectangular template
substrate 2 and a pedestal portion 3 provided on (or approximately
so) a central portion of a first surface 21 of template substrate
2.
The template substrate 2 has, for example, a generally rectangular
flat plate structure. The template substrate 2 is formed of quartz
glass or the like.
The pedestal portion 3 has a quadrangular pyramidal structure. An
uneven pattern 33 that is to be brought into contact with a resist
on a workpiece during the imprint processing is provided on a first
surface 31 of the pedestal portion 3. A pattern arrangement region
R.sub.p and a mark arrangement region R.sub.M provided on an outer
periphery of the pattern arrangement region R.sub.p are provided on
the first surface 31. In FIG. 1A, the pattern arrangement region
R.sub.p is rectangular, and the mark arrangement region R.sub.m
surrounds the pattern arrangement region R.sub.p in a rectangular
frame-like manner. A pattern, corresponding to a wiring pattern or
other device components, to be transferred to the workpiece is
formed in the pattern arrangement region R.sub.p. Marks,
particularly alignment marks for aligning the template 1 with the
workpiece are disposed in the mark arrangement region R.sub.M.
A second surface 32 of the pedestal portion 3 adheres to the first
surface 21 of the template substrate 2. The pedestal portion 3 is
formed of resin such as urethane rubber, silicone rubber, or
acrylate-based rubber. In addition, a thickness of the pedestal
portion 3 is not limited in particular; however, in some examples,
it is preferable that the thickness is approximately 10 .mu.m to 20
.mu.m.
The second surface 32 is smaller (in projected surface area) than
the first surface 31. Accordingly, side surfaces other than the
first surface 31 and the second surface 32 of the pedestal portion
3 are angled from the second surface 32 toward the first surface
31. That is, an angle .alpha. formed between the first surface 31
and a side surface of the pedestal portion 3 is an acute angle
(less than 90 degrees). It is noted that the angle .alpha. is more
preferably greater than or equal to 30 degrees and is less than or
equal to 45 degrees. As such, by configuring the corner portion on
the first surface 31 side as an acute angle, the resist is not
extruded outward from the first surface 31, even if the resist
reaches a peripheral edge portion of the pedestal portion 3 when
the template 1 is pressed against the resist on the workpiece in
the imprint processing. That is, it is possible to prevent the
resist from flowing along the side surface of the pedestal portion
3 during imprint processing.
FIGS. 2A and 2B illustrate an example of a configuration of the
template according to the first embodiment. The more acute the
angle .alpha. of the corner portion on the first surface 31 side
is, the more the resist can be prevented from being extruded to the
side surface of the pedestal portion 3. However, as the angle
.alpha. of the corner portion is reduced, an outer edge 321 of the
second surface 32 moves further towards the center of the pedestal
portion 3. In FIG. 2A, a projected position 321a (a perpendicular
line drawn from the outer edge 321 of the second surface 32 towards
the first surface 31) of the outer edge 321 is within the mark
arrangement region R.sub.M (or alternatively described as outside
the pattern arrangement region R.sub.p). However, in FIG. 2B, the
position 321a is within the pattern arrangement region R.sub.p.
That is, for the arrangement depicted FIG. 2A, the full, maximum
thickness of pedestal portion 3 is below all portions of the
pattern arrangement region R.sub.p. However, for the arrangement
depicted in FIG. 2B, there is a region 325 in which the full,
maximum thickness the pedestal portion 3 is not provided below a
portion of the pattern arrangement region R.sub.p. Here, the "outer
edge" refers to an outer perimeter boundary of the second surface
32 at the interface with surface 21.
In the imprint processing, it is preferable that force is applied
as uniformly as possible in places where the template pattern
exists. Accordingly, for the case illustrated in FIG. 2A, a more
uniform force is applied to the resist contacting the pattern
arrangement region R.sub.p as compared to the case illustrated in
FIG. 2B, in which the region 325 is present below a portion of the
pattern arrangement region R.sub.p and the force applied to the
resist by the template 1 may be different at a position
corresponding to the region 325.
Therefore, it is preferable that the pedestal portion 3 exists at a
uniform thickness below all portions of the pattern arrangement
region R.sub.p, as illustrated in FIG. 2A. Accordingly, it is
preferable that the angle .alpha. of the corner portion on the
first surface 31 side be selected such that the position 321a will
be in the mark arrangement region R.sub.M and not pattern
arrangement region R.sub.p.
Next, a method of manufacturing the template 1 will be described.
FIGS. 3A to 3E illustrate an example of a sequence of the
manufacturing method of a template 1 according to the first
embodiment. First, as illustrated in FIG. 3A, the template
substrate 2 is prepared. The template substrate 2 is formed of, for
example, quartz glass in a form of a rectangular flat plate.
Subsequently, a guide layer 51 is formed on the first surface 21 of
the template substrate 2. The guide layer 51 is formed on the first
surface 21 of the template substrate 2 so as to have an opening 52
having a rectangular shape in an overhead view, in which a width
decreases from an upper surface of the guide layer 51 toward a
lower surface (a boundary with the template substrate 2) of the
guide layer 51. Here, the width indicates, for example, a maximum
width of the opening 52 in any direction parallel to first surface
21. A side surface 52a forming the opening 52 has a tapered shape.
The guide layer 51 is a material with etching selectivity different
from etching selectivity of an embedded material 34. In addition,
it is preferable that the guide layer 51 is a material that does
not substantially intermix with the embedded material 34 and can be
removed by a solvent. For example, polystyrene, polyurethane or the
like which is a chain polymer material can be used as the guide
layer 51.
The opening 52 in the guide layer 51 can be formed, for example, by
an imprinting process performed on the first surface 21 of the
template substrate 2, using an imprint template (e.g., a different
template 1) having a rectangular convex pattern which is pressed
into a material of the guide layer 51. Alternatively, the guide
layer 51 and opening 52 can be formed by a photolithographic
process. At this time, the angle between the upper surface and the
side surface of the guide layer 51 is formed so as to be larger
than 90 degrees. That is, the interior angle of the side surface of
the guide layer 51 and the first surface 21 of the template
substrate 2 is less than 90 degrees.
Thereafter, the embedded material 34 is disposed in the opening 52
as illustrated in FIG. 3B. The embedded material 34 is a
thermosetting resin or a photo-curing resin which, as initially
applied, is unset/uncured to at least some extent. The embedding
material 34 is, for example, a resin material that crosslinks such
as urethane rubber, silicone rubber, or acrylate-based rubber. In a
state depicted in FIG. 3B, the embedded material 34 is not cured
and is in a liquid or flowable state.
Next, as illustrated in FIG. 3C, an original plate 61 is pressed
against the embedded material 34, and a recess portion 611 of the
original plate 61 is filled with the embedded material 34.
Thereafter, heat or light is applied to the embedded material 34,
and thereby, the embedded material 34 is cured. By doing so, the
embedded material 34 becomes the pedestal portion 3. The original
plate 61 is a template for pattern formation having a pattern of
protrusions and recesses formed thereon which is the inverse of the
pattern of protrusions and recesses to be formed on template 1. The
original plate 61 is formed of, for example, quartz glass and may
be referred to as a master template 61 in some contexts.
Next, as illustrated in FIG. 3D, the original plate 61 is detached
from the pedestal portion 3. Furthermore, as illustrated in FIG.
3E, the guide layer 51 is removed by wet processing or the like. In
the wet processing, a chemical solution or solvent in which the
cured embedded material 34 does not dissolve but in which the guide
layer 51 does dissolve or otherwise is removed is used. Thereby,
the pedestal portion 3 having the uneven pattern 33 is formed on
the template substrate 2, and the template 1 is completed.
In the first embodiment, the angle .alpha. between the first
surface 31 on which the pattern of the pedestal portion 3 of the
template 1 is formed and the side surface is less than 90 degrees.
As a result, when the template 1 is pressed against the resist on
the workpiece, it is possible to prevent or limit the resist from
seeping out from the peripheral edge portion of the pedestal
portion 3 and then flowing along the side surface of the pedestal
portion 3. As a result, a height of the resist seeping out to the
side surface of the pedestal portion 3 can be less than, for
example, 100 nm. In addition, defect in a shot region formed when
the next shot region is pressed can be reduced by the cured
resist.
Second Embodiment
In the first embodiment, the angle .alpha. formed between a side
surface and a first surface on which a pattern of a pedestal
portion is formed is less than 90 degrees. As the angle .alpha.
decreases, resist can be prevented from seeping out to the side
surface of the template 1, but in a structure of the first
embodiment, as described with reference to FIG. 2B, a pattern
arrangement region has to be provided within a projected perimeter
(outline) of the second surface of the pedestal portion.
Accordingly, when the angle .alpha. is reduced, a width of a kerf
region has to increase to make an area of the first surface of the
pedestal portion to be larger than a shot region. In the second
embodiment, a template capable of preventing a resist from seeping
from a peripheral edge portion of the pedestal portion while
keeping an area of the pedestal portion substantially the same size
as the shot region will be described.
FIG. 4 is a sectional view schematically illustrating an example of
a configuration of a template 1 according to the second embodiment.
In the second embodiment, a side surface of the pedestal portion 3
is configured to have two distinct portions. A first side surface
portion 35a has a surface substantially perpendicular to the first
surface 21, and a second side surface portion 35b intersects at an
angle .alpha. less than 90 degrees with respect to the first
surface 31 are provided.
Since the angle .alpha. between the second side surface portion 35b
and the first surface 31 is less than 90 degrees, as a distance
from the first surface 21 increases, a position of an outer edge of
the second side surface portion 35b moves. In addition, if a size
(hereinafter, referred to as a height) of the pedestal portion 3 in
a thickness direction is constant, the angle .alpha. formed between
the first surface 31 and the second side surface portion 35b can be
changed by changing the length of the first side surface portion
35a. That is, the greater the length of the first side surface
portion 35a is, the smaller the angle .alpha. will be, and the
shorter the length of the first side surface portion 35a, the
larger the angle .alpha. is.
A position 35c, corresponding to the projected outer edge position
of the first side surface portion 35a, is not located in the
pattern arrangement region R.sub.p provided on the first surface 31
but is located in the mark arrangement region R.sub.M. This is
because, if the projected position of the outer edge of the first
side surface portion 35a is in the pattern arrangement region
R.sub.p, it is impossible to uniformly apply a force to each
position of the resist in contact with the pattern arrangement
region R.sub.p, as described in the first embodiment. It is noted
that the same configuration elements as the configuration elements
of the first embodiment are denoted by the same reference numerals
or symbols, and description thereof will be omitted.
The template 1 of the second embodiment can be manufactured by
substantially the same manufacturing method as the manufacturing
method described in conjunction with the first embodiment. However,
the side surface 52a of the opening 52 of the guide layer 51 formed
on the template substrate 2 (see FIG. 3A) would need to be modified
from the first embodiment to include a part corresponding to the
first side surface portion 35a and a part corresponding to the
second side surface portion 35b.
FIG. 5 is a sectional view schematically illustrating another
example of the structure of a template 1 according to the second
embodiment. In FIG. 4, a case where the first side surface portion
35a of the pedestal portion 3 stands perpendicularly to the first
surface 21 is illustrated. However, as illustrated in FIG. 5, an
interior angle .beta. between the first surface 21 and the first
side surface portion 35a may be less than 90 degrees. However, the
position 35c (that is, the position of closest approach to the
pattern arrangement region R.sub.p) where the outline of the first
side surface portion 35a is the smallest is projected onto the
first surface 31 of the pedestal portion 3 exists in the mark
arrangement region R.sub.M. In addition, while not specifically
illustrated, the angle .beta. formed between the first surface 21
of the template substrate 2 and the first side surface portion 35a
of the pedestal portion 3 may instead be larger than 90 degrees in
some embodiments. Furthermore, the first side surface portion 35a
may have a surface (R surface) with a curvature (radius of
curvature) or may have another surface shape.
According to the second embodiment, substantially the same effects
as the first embodiment can be obtained.
Third Embodiment
In the first embodiment, a pattern on template 1 is formed by
pressing an original template into an embedded material and curing
the embedded material. However, the disclosure is not limited to
this. In the third embodiment, another method of manufacturing a
template will be described.
FIGS. 6A to 6D are sectional views illustrating an example of a
sequence of a manufacturing method of a template according to the
third embodiment. As an initial step a process similar to those
described in conjunction with FIGS. 3A and 3B in the first
embodiment is performed. As such, the embedded material 34 is cured
by applying heat or light to the embedded material 34 buried in the
opening 52 of the guide layer 51. Then, the guide layer 51 is
removed. By doing so, an embedded portion 34a formed of a resin is
formed on the template substrate 2, as depicted in FIG. 6A. The
embedded portion 34a corresponds to a pedestal portion 3 on which
the pattern 33 has not been formed.
Next, as illustrated in FIG. 6B, an original plate 62 on which a
pattern has been formed is coated with a receiver material 36a. The
receiver material 36a is applied onto the original plate 62 by
using, for example, a spin coating method. The receiver material
36a is filled into a recess pattern in the original plate 62. The
original plate 62 is a template for pattern formation having a
pattern on one side. The original plate 62 is, for example, a
silicon substrate. Unlike the original plate 61 described in FIGS.
3A to 3E, the original plate 62 is not provided with the pedestal
portion 3. The receiver material 36a is, for example, a resin
material which crosslinks such as urethane rubber, silicone rubber
or acrylate-based rubber. In the state depicted in FIG. 6B, the
receiver material 36a is not cured and is a liquid or flowable
material.
Thereafter, as illustrated in FIG. 6C, the original plate 62 coated
with the receiver material 36a is disposed so as to face the
embedded portion 34a1, and the receiver material 36a is brought
into contact with the embedded portion 34a. In this state, heat or
light is applied to the receiver material 36a, and the receiver
material 36a is cured and a transfer portion 36 is formed. The
transfer portion 36 is bonded to the embedded portion 34a.
Next, as illustrated in FIG. 6D, the template substrate 2 is
separated from the original plate 62. Thereby, the pedestal portion
3 on which the transfer portion 36 is provided is formed. As
described above, a template 1 corresponding to that depicted in
FIGS. 1A and 1B is completed.
In the third embodiment, it is possible to manufacture the template
1 in which the angle .alpha. of the corner portion formed between
the first surface 31 and the side surface of the pedestal portion 3
is less than 90 degrees, when the thin transfer portion 36 is
discounted. Thereby, the following effect is achieved. That is, it
is possible to obtain the template 1 for which the resist will not
substantially seep out from the outer periphery portion of the
pedestal portion 3 during the template pressing.
Fourth Embodiment
In a fourth embodiment, a method of manufacturing a template having
a structure in which a transfer portion formed of a patterned resin
is provided on a pedestal portion of a template substrate, will be
described.
FIG. 7 is a sectional view schematically illustrating an example of
a configuration of a template 1 according to the fourth embodiment.
The template 1 according to the fourth embodiment includes a
template substrate 2a and the transfer portion 36. The template
substrate 2a has a configuration in which a pedestal portion 24 is
provided near a central portion of the first surface 21 of a
rectangular substrate. The pedestal portion 24 has a structure
protruding by approximately 10 to 50 .mu.m with respect of the rest
of the template substrate 2a. In performing this process, an angle
formed between the side surface and a surface on a side where the
transfer portion 36 of the pedestal portion 24 is disposed is not
limited to an angle illustrated in FIG. 7. The angle of the
pedestal portion 24 may be greater than or equal to, for example,
90 degrees. However, it is also possible to obtain the effect
described in the first embodiment by setting the angle of the
pedestal portion 24 to be less than 90 degrees. The template
substrate 2a is formed of quartz glass or the like.
The transfer portion 36 has a pattern of protrusions and recesses
on the first surface 361 and forms the patterned portion of
template 1. The second surface 362 opposite to the first surface
361 adheres onto the pedestal portion 24 of the template substrate
2a. As illustrated in FIG. 1A, the pattern arrangement region
R.sub.p, of a rectangular shape, and the mark arrangement region
R.sub.M, of a frame shape surrounding the pattern arrangement
region R.sub.p, are provided on the first surface 361. A pattern
disposed in the pattern arrangement region R.sub.p and a mark
disposed in the mark arrangement region R.sub.M are substantially
the same as the pattern and the mark described in conjunction with
the first embodiment. The transfer portion 36 is formed of a
flowable material including a reactive group for purposes of
curing/hardening the material. The material may be a
photo-initiated radical polymerizable material including at least
one reactive group selected from an acryloyl group, a methacryloyl
group, or a vinyl ether group, or a photo-initiated cationic
polymerizable material including at least one reactive group
selected from an epoxy group or an oxetanyl group is exemplified as
a reactive group for curing.
FIGS. 8A to 8D are cross-sectional views schematically illustrating
an example of a sequence for a manufacturing a template 1 according
to the fourth embodiment. First, as illustrated in FIG. 8A, an
original plate 62 having a pattern etched therein corresponding to
that to be formed on the template 1 is prepared. The original plate
62 is provided with a plurality of recess portions 62a. The
original plate 62 is, for example, a silicon substrate.
Next, as illustrated in FIG. 8B, a receiver material 36a that is a
liquid is formed on the original plate by using a spin coating
method. The receiver material 36a is filled in the recess portions
62a and a thickness of the receiver material 36a above the pattern
formation surface of the original plate is substantially
uniformized. A photo-curing resin or the like can be used as the
receiver material 36a.
Thereafter, the template substrate 2a is disposed such that the
pedestal portion 24 faces the receiver material 36a on the original
plate 62. The template substrate 2a is formed of quartz glass or
the like and is provided with the pedestal portion 24 having a
height of approximately 10 to 50 .mu.m positioned near a central
portion of the first surface 21.
Next, as illustrated in FIG. 8C, the template substrate 2a is
brought into contact with the receiver material 36a. Thereafter,
the receiver material 36a in contact with the pedestal portion 24
is irradiated with ultraviolet rays. Thereby, the receiver material
36a in the region irradiated with the ultraviolet rays is cured to
form the solidified, cured transfer portion 36, but the receiver
material 36a in the regions not irradiated with the ultraviolet
rays remains in a liquid, uncured form.
Next, as illustrated in FIG. 8D, the template substrate 2a is
separated from the original plate 62. The transfer portion 36
(cured receiver material 36a) is peeled from the original plate 62
and the uncured receiver material 36a remains on the original plate
62. It is noted that the internal breaking strength (modulus) of
the transfer portion 36 is preferable to be greater than or equal
to 1.2.times.10.sup.-4 GPa. This is because, when the template 1 is
peeled from the resist in the imprint processing, the transfer
portion 36 might be broken unless the transfer portion has a
breaking stress greater than or equal to 1.2.times.10.sup.-4
GPa.
FIGS. 9A to 9D are cross-sectional views schematically illustrating
an example of a sequence of a method of manufacturing a
semiconductor device using a template 1 according to the fourth
embodiment. First, as illustrated in FIG. 9A, a resist 71 is
dispense onto a particular die or shot region of a workpiece 70.
The resist 71 is, for example, a photo-curing resin. The resist 71
is dispensed onto the workpiece 70 by using, for example, an inkjet
method. Alternatively, the resist 71 may be entirely coated over
the workpiece 70 by using the spin coating method. The workpiece 70
is a semiconductor substrate such as a silicon substrate, a
semiconductor film formed over a semiconductor substrate, a
conductive film, or an insulating film. Next, in a state where the
transfer portion 36 of the template 1 faces the workpiece 70, rough
positioning (coarse alignment) between the template 1 and the
workpiece 70 is performed.
Thereafter, as illustrated in FIG. 9B, at least one of the template
1 and the workpiece 70 is moved until the transfer portion 36 comes
into contact with the resist 71. Then, more precise positioning
(fine alignment) between the template 1 and the workpiece 70 is
performed. After the resist 71 is filled in recess portions of the
template 1, the resist 71 is irradiated with ultraviolet rays to
cure the resist 71. Thereby, a resist pattern 71a is formed.
Next, as illustrated in FIG. 9C, the template 1 is separated from
the resist pattern 71a. Thereafter, the workpiece 70 is processed
by using anisotropic etching, such as reactive ion etching (RIE),
using the resist pattern 71a as a mask. By repeating this
processing, the workpiece 70 can be processed to have a desired
pattern, and a semiconductor device having the desired pattern is
thereby manufactured.
Here, if a processing is repeated in which the template 1 is
pressed against the resist 71 on the workpiece 70 many times and
the resist 71 is separated from the resist pattern 71a after being
cured, the pattern of the transfer portion 36 might eventually be
damaged as illustrated in FIG. 9D. If the imprint processing is
performed by using a damaged template 1 (see FIG. 9D), the intended
resist pattern 71a is no longer able to be formed on the workpiece
70. In such a case, the damaged transfer portion 36 must be removed
and a new transfer portion 36 formed on the pedestal portion 24 of
the template substrate 2a, and thereby, the template 1 can be more
easily reproduced or repaired.
FIGS. 10A and 10B are cross-sectional views schematically
illustrating an example of a sequence for repairing the template 1
according to the fourth embodiment. First, as illustrated in FIG.
10A, the damaged transfer portion 36 of the template 1 is peeled or
otherwise removed by a cleaning process. For example, a sulfuric
acid hydrogen peroxide solution (sometimes referred to as piranha
etch) can be used as a cleaning solution, but the cleaning solution
may be appropriately changed depending on the material of the
transfer portion 36. Thereby, the template substrate 2a in which an
upper portion of the pedestal portion 24 has been cleaned is
obtained as illustrated in FIG. 10B.
Thereafter, in substantially the same manner as in the method
illustrated in FIGS. 8A to 8D, the template 1 is reproduced by
forming a new transfer portion 36 on the pedestal portion 24 of the
template substrate 2a. The remade template 1 can then be used for
manufacturing semiconductor devices as illustrated in FIGS. 9A to
9D.
In the fourth embodiment, imprint processing is performed by using
the template 1 in which the resin transfer portion 36 having a
pattern adheres onto the pedestal portion 24. When the transfer
portion 36 is damaged, the transfer portion 36 can be removed and a
new transfer portion 36 can be formed on the pedestal portion 24.
When a template formed entirely of quartz glass is damaged, the
entire template must be discarded, but in the fourth embodiment,
the template 1 can be re-manufactured at a low cost, compared to
the manufacturing cost of a quartz glass template since generally,
the template substrate 2a is not damaged and can thus be reused
after only a relatively simple cleaning process.
In addition, after an upper portion of the original plate 62 is
coated with the receiver material 36a by using the spin coating
method, the receiver material 36a in contact with the template
substrate 2a is cured. Accordingly, a film thickness of the
transfer portion 36 formed on the pedestal portion 24 of the
template substrate 2a can be substantially uniformized.
Fifth Embodiment
In the template manufacturing method according to the fourth
embodiment, after a receiver material is cured in a state of being
in contact with a template substrate and the template substrate is
separated from the original plate, occasionally the cured receiver
material might not adhere to the template substrate and thus might
remain on the original plate sometimes. In the fifth embodiment, a
method of avoiding such a case will be described.
FIG. 11 is a sectional view schematically illustrating an example
of a template according to the fifth embodiment. The template 1
further includes an adhesion layer 5 between the template substrate
2a and the transfer portion 36. A material having an adhesion
strength towards the transfer portion 36 that is larger than the
adhesion strength between the transfer portion 36 and the original
plate 62 is used as the adhesion layer 5.
The adhesion layer 5 can provide improved adhesion strength by
incorporating a material providing hydrogen bonding to the relevant
surfaces/materials and/or covalent bonding linkages between the
template substrate 2a and the transfer portion 36. In an example,
adhesion layer 5 is formed of a material having a reactive group
that bonds with the transfer portion 36 and a reactive group bonds
with the template substrate 2a. As described in the fourth
embodiment, the transfer portion 36 also requires a reactive group
for curing. For example, in a case where the transfer portion 36
has a photo radical polymerizable group, the photo radical
polymerizable group may also be the reactive group for bonding with
the transfer portion 36. The material containing a photo radical
polymerizable group contains at least one reactive group selected
from an acryloyl group, a methacryloyl group, and a vinyl ether
group. In addition, in a case where the transfer portion 36
contains a photo cationic polymerizable group, the photo cationic
polymerizable group may also be the reactive group for bonding with
the transfer portion 36. The material containing a photo cationic
polymerizable group contains at least one reactive group selected
from an epoxy group and an oxetanyl group.
In a case where the template substrate 2a is formed of quartz
glass, a silane coupling agent can be used as a reactive group for
bonding with the template substrate 2a. Monoalkoxysilanes,
dialkoxysilanes, trialkoxysilanes, monochlorosilanes,
dichlorosilanes, trichlorosilanes, and the like can be used as the
silane coupling agent. Accordingly, for example, a silane coupling
agent also containing a photo radical polymerizable group, a silane
coupling agent also containing a photo cationic polymerizable
group, or the like can be used as the adhesion layer 5.
3-(Trimethoxysilyl)propyl acrylate, 3-[diethoxy(methyl)silyl]propyl
methacrylate, 3-(trimethoxysilyl)propyl methacrylate,
3-[tris(trimethylsilyloxy)silyl]propyl methacrylate,
3-[Dimethoxy(methyl)silyl]propyl methacrylate,
3-(methoxydimethylsilyl)propyl acrylate, 3-(triethoxysilyl)propyl
methacrylate, 3-(triallylsilyl)propyl acrylate,
3-(triallylsilyl)propyl methacrylate,
diethoxy(3-glycidyloxypropyl)methylsilane,
3-glycidyloxypropyltrimethoxysilane,
3-glycidyloxypropyl(dimethoxy)methylsilane,
[8-(glycidyloxy)-n-octyl]trimethoxysilane,
triethoxy(3-glycidyloxypropyl)silane, and the like can be used as
the adhesion layer 5 in various example embodiments.
FIG. 12 is a diagram schematically illustrating a role of the
adhesion layer in the template 1 according to the fifth embodiment.
Here, a case where 3-(trimethoxysilyl)propyl acrylate is used as
the adhesion layer 5 is taken as an example. As illustrated in FIG.
12, a trimethoxysilyl group of the adhesion layer 5 bonds to the
template substrate 2a formed of quartz glass by a silane coupling
reaction. The acryloyl group of the adhesion layer 5 bonds to the
transfer portion 36 in the photo polymerization reaction used for
curing of the transfer portion 36. As such, the adhesion layer 5
can make the template substrate 2a more firmly adhere to the
transfer portion 36.
If the acryloyl group is switched to an epoxy group, which is a
photo cationic polymerizable group, the epoxy group bonds to the
transfer portion 36 by a photo cationic polymerization reaction
during curing of the transfer portion 36.
FIGS. 13A to 13E are cross-sectional view schematically
illustrating an example of a sequence of a manufacturing method of
a template 1 according to the fifth embodiment. Here, a case where
the adhesion layer 5 and the receiver material 36a are configured
with a material containing a photo radical polymerizable group will
be described as an example.
First, as illustrated in FIG. 13A, the adhesion layer 5 is formed
on the pedestal portion 24 of the template substrate 2a by using a
film formation method such as a vapor deposition method. Here,
3-(trimethoxysilyl)propyl acrylate is used for the adhesion layer
5, the trimethoxysilyl group bonds to the template substrate 2a,
which is formed of quartz glass, through a silane coupling reaction
during the vapor deposition process, and thereby, the adhesion
layer 5 is formed.
Next, as illustrated in FIG. 13B, the original plate 62 is
prepared, and the receiver material 36a is formed on the entire
surface of the original plate 62 by using the spin coating
method.
Thereafter, the template substrate 2a is disposed such that the
pedestal portion 24 faces the receiver material 36a on the original
plate 62. Next, as illustrated in FIG. 13C, the template substrate
2a and the receiver material 36a are brought into contact. However,
unlike the case of FIG. 8C, the receiver material 36a is brought
into direct contact with the adhesion layer 5 formed on the
pedestal portion 24 instead of the pedestal portion 24. During this
contacting process, the template substrate 2a and the original
plate 62 are disposed in an atmosphere in which the curing reaction
is inhibited. That is, in a case where the receiver material 36a
containing a photo radical polymerizable group is used, the
atmosphere contains oxygen.
Thereafter, as illustrated in FIG. 13D, a region including the
pedestal portion 24 is irradiated with ultraviolet rays. By doing
so, the adhesion layer 5 and the receiver material 36a are bonded
to each other by the photo radical polymerization reaction and are
cured in the irradiated region where the adhesion layer 5 and the
receiver material 36a are in contact with each other. As a result,
the receiver material 36a becomes the transfer portion 36. It is
preferable that only a region corresponding to the pedestal portion
24 is irradiated with ultraviolet rays, but generally a wider
region than the region exactly corresponding to the pedestal
portion 24 will usually be irradiated with the ultraviolet rays.
Since the pedestal portion 24 protrudes from the first surface 21
of the template substrate 2a, a periphery of the pedestal portion
24 is filled in an atmosphere containing oxygen. In an oxygen rich
atmosphere, a photo radical polymerizable curing reaction will not
substantially progress and the receiver material 36a exposed to the
oxygen rich atmosphere during irradiation is hardly solidified, and
thus, even if some periphery of the pedestal portion 24 is
irradiated with ultraviolet rays, the receiver material 36a
disposed beyond the pedestal portion 254 will not be substantially
cured and therefor remains in a liquid form in those regions which
are not in direct contact with the adhesion layer 5.
Next, as illustrated in FIG. 13E, the template substrate 2a is
separated from the original plate 62. The transfer portion 36 is
peeled not from the template substrate 2a but from a boundary with
the original plate 62 without being broken. In addition, since the
receiver material 36a is not cured in regions other than the region
corresponding to the pedestal portion 24 of the template substrate
2a, the breaking stress of the transfer portion 36 in the region
corresponding to the pedestal portion 24 is larger than the
breaking stress of the receiver material 36a in the regions other
than the region corresponding to the pedestal portion 24.
Accordingly, when being separated, the transfer portion 36 is
cleanly peeled at a boundary between the region corresponding to
the pedestal portion 24 and the other regions.
The adhesion layer 5 and the receiver material 36a can be
configured with a material containing a photo cationic
polymerizable group. In such cases, when these materials are in an
atmosphere including water vapor, the photo cationic polymerization
curing reaction will be inhibited (similarly to inhibition of the
radical polymerization curing reaction by the presence of oxygen).
Accordingly, in a case where the adhesion layer 5 and the receiver
material 36a are configured with a material containing a photo
cationic polymerizable group, the template substrate 2a and the
original plate 62 are disposed in an atmosphere containing water
vapor before the ultraviolet rays are applied in FIG. 13D. By doing
so, the adhesion layer 5 and the receiver material 36a are bonded
to each other and cured by photo cationic polymerization reaction
in the region where the adhesion layer 5 and the receiver material
36a are in contact with each other. In the other regions where the
receiver material 36a is not in contact with the adhesion layer 5,
the receiver material 36a is not cured due to inhibition by water
vapor and thus remains in a liquid form.
The same effect as in the fourth embodiment can also be obtained in
the fifth embodiment.
Sixth Embodiment
FIG. 14 is a cross-sectional view schematically illustrating an
example of a template manufactured by using the method described in
the fourth embodiment. As illustrated in FIG. 14, the transfer
portion 36 is provided on the pedestal portion 24 of the template
substrate 2a; however, a peripheral edge portion of the transfer
portion 36 in contact with the pedestal portion 24 may occasionally
be formed having an unintended, irregular shape. For example, a
portion 363 of the peripheral edge portion of the transfer portion
36 may protrude more in a lateral direction than an outer edge of
the pedestal portion 24. If the imprint processing is performed by
using such a template, there is a possibility that the portion
protruding in the lateral direction would interfere with a resist
pattern formed or to be formed in an adjacent shot or die region.
In addition, the same problem may occur with the fifth embodiment.
In the sixth embodiment, a method of manufacturing a template that
can prevent such a problem from occurring will be described.
FIGS. 15A and 15B are cross-sectional views schematically
illustrating an example of a sequence of a template manufacturing
method according to the sixth embodiment. FIG. 15A illustrates the
template 1 after separation from the original plate 62 as in FIG.
8D. As illustrated in FIG. 15A, the transfer portion 36 includes a
convex portion (convex pattern) 365 and a residual film portion 366
having a substantially uniform thickness on the pedestal portion 24
of the template substrate 2a. A recess portion (recess pattern) is
a region surrounded by or between the convex portion 365. As
illustrated in FIG. 14, a peripheral edge portion of the residual
film portion 366 may occasionally protrude outside of the pedestal
portion 24.
As illustrated in FIG. 15B, an etch-back process is performed by
anisotropic dry etching, such as a RIE method, until exposed
portions of the residual film portion 366 are removed.
It is noted that a case corresponding to the fourth embodiment is
described as an example here, but both exposed portions of the
residual film portion 366 and the adhesion layer 5 (present as in
the fifth embodiment) can be removed in the etch-back process.
Likewise, in the sixth embodiment, the receiver material 36a is
cured, the template substrate 2a is separated from the original
plate 62, and thereafter, the exposed portions of the residual film
portion 366 can be removed by anisotropic etching. By doing so, it
is possible to prevent the peripheral edge portion of the residual
film portion 366 from protruding in the lateral direction and
interfering with a resist pattern formed or to be formed in the
adjacent regions.
While certain embodiments have been described, these embodiments
have been presented by way of examples only, and are not intended
to limit the scope of the inventions. Indeed, the novel embodiments
described herein may be embodied in a variety of other forms;
furthermore, various omissions, substitutions and changes in the
form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *